Sorting device that decides loading level of output tray by moving sheet sensor

ABSTRACT

A sorting device includes a plurality of output trays, a sheet sensor, a displacement mechanism, and a controller. The plurality of output trays are aligned in a predetermined direction, and configured to receive the sheets. The sheet sensor detects the sheet placed on the output tray. The displacement mechanism is configured to move the first sheet sensor in a predetermined direction along the plurality of output trays, in a predetermined increment of displacement amount. The controller includes a processor, and changes a sheet detecting position of the first sheet sensor in stages, by controlling an operation of the displacement mechanism so as to move the first sheet sensor in the predetermined increment of the displacement amount, and decides a loading level of the output tray, according to whether the first sheet sensor has detected the sheet, when the processor executes a control program.

INCORPORATION BY REFERENCE

This application claims priority to Japanese Patent Application No. 2022-041566 filed on Mar. 16, 2022, the entire contents of which are incorporated by reference herein.

BACKGROUND

The present disclosure relates to a sorting device that sorts sheets delivered from an image forming apparatus.

A sorting device (mail box) is known, as an optional device for an image forming apparatus such as a copier or a multifunction peripheral. The sorting device includes a plurality of output trays, and serves to sort sheets delivered from the image forming apparatus.

SUMMARY

The disclosure proposes further improvement of the foregoing techniques.

In an aspect, the disclosure provides a sorting device that sorts sheets. The sorting device includes a plurality of output trays, a first sheet sensor, a displacement mechanism, and a controller. The plurality of output trays are aligned in a predetermined direction, and configured to receive the sheets. The first sheet sensor detects the sheet placed on the output tray. The displacement mechanism is configured to move the first sheet sensor in a predetermined direction along the plurality of output trays, in a predetermined increment of displacement amount. The controller includes a processor, and changes a sheet detecting position of the first sheet sensor in stages, by controlling an operation of the displacement mechanism so as to move the first sheet sensor in the predetermined increment of the displacement amount, and decides a loading level of the output tray, according to whether the first sheet sensor has detected the sheet, when the processor executes a control program.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic front view showing a part of an image forming system including a sorting device according to an embodiment of the disclosure;

FIG. 2A is a schematic front view showing a part of the structure of the sorting device;

FIG. 2B is a right side view showing a part of the structure of the sorting device;

FIG. 3 is a functional block diagram schematically showing an essential internal configuration of the image forming system;

FIG. 4 is a flowchart showing an example of a preparatory operation, performed by a controller of the sorting device;

FIG. 5A and FIG. 5B, and FIG. 6A to FIG. 6C are schematic drawings each showing a principle for deciding the loading level of an output tray;

FIG. 7A is a schematic front view showing a part of the structure of a switching device;

FIG. 7B is a schematic cross-sectional view showing a part of the structure of a first guide member and a second guide member; and

FIG. 8 is a functional block diagram schematically showing an essential internal configuration of an image forming system according to another embodiment of the disclosure.

DETAILED DESCRIPTION

Hereafter, a sorting device according to an embodiment of the disclosure will be described, with reference to the drawings. FIG. 1 is a schematic front view showing a part of an image forming system 10 including the sorting device 2 according to the embodiment of the disclosure. The image forming system 10 includes an image forming apparatus 1 that forms an image on a sheet, and the sorting device 2 provided on the upper side of the image forming apparatus 1.

The image forming apparatus 1 is a multifunction peripheral having a plurality of functions, such as copying, printing, scanning, and facsimile transmission. The sorting device 2 serves to sort the sheets delivered from the image forming apparatus 1. The sorting device 2 includes a plurality of output trays 21A to 21D (hereinafter, simply “output tray 21” as the case may be) on which the sheets are to be stacked. The plurality of output trays 21A to 21D are aligned in the up-down direction (i.e., vertical direction), corresponding to the predetermined direction in the disclosure.

FIG. 2A is a schematic front view showing a part of the structure of the sorting device 2. FIG. 2B is a right side view showing a part of the structure of the sorting device 2. The sorting device 2 includes the plurality of output trays 21A to 21D, a transport device for delivery 22 (see FIG. 3 ), a switching device 23, a displacement mechanism 24, a home position sensor 25, and a controller 26. The transport device for delivery 22 transports the sheet P delivered from the image forming apparatus 1, to the output tray 21. The switching device 23 changes the transport direction of the sheet P, to guide the sheet P to one of the plurality of output trays 21A to 21D. The displacement mechanism 24 is configured to move the switching device 23 along the plurality of output trays 21A to 21D, in a predetermined direction and in a predetermined increment of displacement amount M1.

The transport device for delivery 22 includes a transport route for delivery, a transport roller, and a drive motor. The transport route for delivery extends in the up-down direction, from the connection point to the image forming apparatus 1 as far as the upper end portion of the sorting device 2. The drive motor causes the transport roller to rotate. The transport device for delivery 22 transports upward the sheet P delivered from the image forming apparatus 1, to the position of the switching device 23.

The switching device 23 is configured to move in the up-down direction, in other words in the direction in which the plurality of output trays 21A to 21D are aligned, to guide the sheet P to one of the plurality of output trays 21A to 21D. For example, the switching device 23 includes a flapper 232, for switching the delivery destination of the sheet P via a delivery roller 238 (see FIG. 7A). The switching device 23 switches, by using the flapper 232, the proceeding direction of the leading edge of the sheet P, being transported by the transport device for delivery 22, to the output tray 21 designated as the delivery destination, thereby guiding the sheet P to the output tray 21 designated as the destination. Accordingly, the sheet P is guided to the output tray 21 located at the height corresponding to the position where the switching device 23 is at a stop.

The displacement mechanism 24 includes a drive roller 241, a follower roller 242, a carrying belt 243, and a drive motor 244. The carrying belt 243 is stretched between the drive roller 241 and the follower roller 242. The drive motor 244 causes the drive roller 241 to rotate. The switching device 23 is fixed to the carrying belt 243. The switching device 23 is moved up and downward along the plurality of output trays 21A to 21D, by the rotation of the drive motor 244. The drive motor 244 is configured to accept positioning control (e.g., a stepping motor). Therefore, the controller 26 can control the displacement mechanism 24 so as to move the switching device 23 in the increment of displacement amount M1.

The switching device 23 includes a first sheet sensor 231. The first sheet sensor 231 detects the sheet P placed on the output tray 21. The first sheet sensor 231 moves, together with the switching device 23 moved by the displacement mechanism 24, along the direction in which the plurality of output trays 21A to 21D are aligned. The first sheet sensor 231 is, for example, a reflective optical sensor including a light emitting element that emits light to the sheet P, and a photodetector that detects the light reflected by the sheet P.

The home position sensor 25 is located forward of the switching device 23, inside the main body of the sorting device 2. The home position sensor 25 serves to detect the arrival and passing of the switching device 23 at the home position, and is utilized to recognize the current position of the switching device 23. For example, a reflective or transmissive optical sensor is employed, as the home position sensor 25.

FIG. 3 is a functional block diagram showing an essential internal configuration of the image forming system 10. The image forming apparatus 1 includes a document feeding device 11, a document reading device 12, an image forming device 13, a fixing device 14, a paper feeding device 15, an operation device 16, a storage device 17, a controller 18, and a communication interface (I/F) 19.

The document feeding device 11 is openably connected to the upper face of the document reading device 12, for example via a hinge. The document feeding device 11 serves as a document retention cover, when the document reading device 12 reads a source document placed on the platen glass. The document feeding device 11 is an automatic document feeder, abbreviated as ADF. The document feeding device 11 includes a document tray, and delivers the source documents placed thereon to the document reading device 5, one by one.

To perform the document reading operation, the image forming apparatus 1 operates as follows. The document reading device 12 optically reads the image on the source document delivered from the document feeding device 11 to the document reading device 12, or placed on the platen glass, and generates image data. The image data generated by the document reading device 5 is stored, for example, in an image memory.

To perform the image forming operation, the image forming apparatus 1 operates as follows. The image forming device 13 forms a toner image on a sheet, serving as the recording medium and delivered from the paper feeding device 14, on the basis of the image data generated through the document reading operation, image data stored in the image memory, or image data received from a computer connected via a network.

The fixing device 14 heats and presses the sheet on which the toner image has been formed by the image forming device 13, to thereby fix the toner image on the sheet. The sheet that has undergone the fixing process is delivered to the sorting device 2. The paper feeding device 15 includes a paper cassette.

The operation device 16 receives the user's instructions to execute the functions and operations that the image forming apparatus 1 is configured to perform, such as the image forming operation. The operation device 16 includes a display device 161 for displaying, for example, an operation guide for the user. The operation device 16 receives, through a touch panel provided on the display device 161, the user's instruction based on an operation (touch operation) performed by the user on the operation screen displayed on the display device 161. The operation device 16 also receives an input of the user's instruction, according to the user's operation performed on a physical key provided in the operation device 16.

The display device 161 includes, for example, a liquid crystal display (LCD). The display device 161 includes the touch panel. When the user touches a button or a key displayed on the screen, the touch panel receives the instruction corresponding to the touched position.

The storage device 17 is a large-capacity storage device such as a hard disk drive (HDD) and a solid state drive (SSD). The storage device 17 contains various control programs.

The controller 18 includes a processor, a random-access memory (RAM), a read-only memory (ROM), and an exclusive hardware circuit. The processor is, for example, a central processing unit (CPU), an application specific integrated circuit (ASIC), or a micro processing unit (MPU). The controller 18 executes the control program stored in the ROM or storage device 17, thereby acting as a processing device that executes the operations necessary for the image forming by the image forming apparatus 1.

The controller 18 serves to control the overall operation of the image forming apparatus 1. The controller 18 is connected to the document feeding device 11, the document reading device 12, the image forming device 13, the fixing device 14, the paper feeding device 15, the operation device 16, the storage device 17, and the communication I/F 19, and controls the mentioned components.

The sorting device 2 includes the output trays 21A to 21D, the transport device for delivery 22, the switching device 23, the displacement mechanism 24, the home position sensor 25, the controller 26, and a communication I/F 27. The cited components (except for the output tray 21) are configured to transmit and receive data and signals to and from each other, via a bus.

The controller 26 includes a processor, a RAM, and a ROM. The controller 26 is connected to the transport device for delivery 22, the switching device 23, the displacement mechanism 24, the home position sensor 25, and the communication I/F 27, and controls the mentioned components.

The controller 18 of the image forming apparatus 1 and the controller 26 of the sorting device 2 input and output data and signals between each other, via the respective communication I/Fs 19 and 27. For example, the controller 18 of the image forming apparatus 1 outputs a control signal instructing the execution of the sorting operation, to the controller 26 of the sorting device 2. The controller 26 of the sorting device 2 controls the action of the transport device for delivery 22, the displacement mechanism 24, and the switching device 23, in response to the control signal received.

The controller 26 controls the action of the displacement mechanism 24 (more specifically, drive motor 244), so as to move the first sheet sensor 231 (switching device 23). The controller 26 also controls the action of the displacement mechanism 24, so as to move the first sheet sensor 231 in the increment of displacement amount M1, thereby changing the detecting position of the sheet P by the first sheet sensor 231 in stages, and decide the loading level of the output tray 21, on the basis of the detection result from the first sheet sensor 231.

Hereunder, an example of a preparatory operation performed by the controller 26 of the sorting device 2 will be described, with reference to a flowchart shown in FIG. 4 . The preparatory operation is for facilitating the sorting operation of the sheet P. The controller 26 executes the preparatory operation, upon receipt of the control signal instructing the execution of the sorting operation, transmitted from the controller 18 of the image forming apparatus 1.

The controller 26 of the sorting device 2 controls the drive motor 244 of the displacement mechanism 24, so as to move the switching device 23 along the plurality of output trays 21A to 21D (step S1). Upon deciding that the switching device 23 has reached the home position, on the basis of the detection signal outputted from the home position sensor 25, the controller 26 causes the switching device 23 to stop moving (step S2). In other words, the controller 26 locates the switching device 23 at the home position.

The controller 26 controls the action of the drive motor 244, so as to move the switching device 23 to one of the output trays 21A to 21D, designated as the delivery destination, according to the control signal (step S3). For example, the controller 26 defines the height of a lower-limit position for receiving the sheet P, on the output tray 21 designated as the delivery destination, as a target position, and causes the switching device 23 to stop moving, when (the center of) the first sheet sensor 231 reaches the target position. Thus, the controller 26 locates the first sheet sensor 231 at the lower-limit position of the output tray 21. FIG. 5A and FIG. 5B each illustrate the state where the first sheet sensor 231 is located at the lower-limit position of the output tray 21.

The displacement amount of the switching device 23 (first sheet sensor 231) per unit time can be determined from the rotation speed of the drive motor 244. Accordingly, the controller 26 can accurately stop the switching device 23 at the target position, by adjusting the working time of the drive motor 244. In the case where a stepping motor is employed as the drive motor, the displacement amount can be controlled by adjusting the number of drive pulses to the stepping motor.

The controller 26 acquires the detection signal outputted from the first sheet sensor 231 (step S4), and decides whether the detection signal from the first sheet sensor 231 is ON (step S5). In the case of detecting the sheet P, the first sheet sensor 231 outputs the ON signal. Otherwise, the first sheet sensor 231 outputs an OFF signal.

When the first sheet sensor 231 is located at the lower-limit position, and the sheets P are stacked on the output tray 21 as shown in FIG. 5A, the detection signal outputted from the first sheet sensor 231 is ON. In contrast, when the first sheet sensor 231 is located at the lower-limit position, and no sheet P is on the output tray 21 as shown in FIG. 5B, the detection signal outputted from the first sheet sensor 231 is OFF. Here, the “lower-limit position” in the drawings indicates the position for detecting that the output tray 21 is empty. An “upper-limit position” in the drawings indicates the position for detecting that the output tray 21 is full.

Upon deciding that the detection signal outputted from the first sheet sensor 231 is ON, in other words that the presence of the sheet P has been detected (YES at step S5), the controller 26 decides whether the first sheet sensor 231 is located at the upper-limit position (step S6).

In this case, the controller 26 decides that the first sheet sensor 231 is not located at the upper-limit position (NO at step S6), and controls the action of the drive motor 244 so as to move switching device 23 (first sheet sensor 231) upward, by a predetermined displacement amount M2, which is an integral multiple of the increment of displacement amount M1 (step S7). In other words, the controller 26 lifts up the first sheet sensor 231 by one stage. The controller 26 defines, for example, one tenth of the distance between the upper-limit position and the lower-limit position shown in FIG. 5A and FIG. 5B, as the displacement amount M2.

After step S7, the controller 26 acquires the detection signal outputted from the first sheet sensor 231 (step S4), and decides whether the detection signal from the first sheet sensor 231 is ON (step S5).

Upon deciding that the detection signal outputted from the first sheet sensor 231 is OFF, in other words that the presence of the sheet P has not been detected (NO at step S5), the controller 26 causes the switching device 23 (first sheet sensor 231) to stop moving at this point, and decides the loading level of the output tray 21, on the basis of the current position of the first sheet sensor 231 (step S8).

Here, it will be assumed that the loading level of the output tray 21 is 50%, as shown in FIG. 6A to FIG. 6C. In such a case, when the first sheet sensor 231 is located at the position lifted up by five stages (5 times of the displacement amount M2) from the lower-limit position as shown in FIG. 6B, the detection signal outputted from the first sheet sensor 231 is ON. As a matter of course, when the first sheet sensor 231 is located at the lower-limit position as shown in FIG. 6A also, the detection signal outputted from the first sheet sensor 231 is ON.

In contrast, when the first sheet sensor 23 is located at the position lifted up by six stages (6 times of the displacement amount M2) from the lower-limit position as shown in FIG. 6C, the detection signal outputted from the first sheet sensor 231 is OFF. Accordingly, the controller 26 can decide that the loading level of the output tray 21 is “equal to or higher than 50%, but lower than 60%”. Shifting thus the sheet detecting position of the first sheet sensor 231 in stages enables the loading level of the output tray 21 to be decided.

Then the controller 26 transmits the information indicating the decision result to the controller 18 of the image forming apparatus 1, via the communication I/F 27 (step S9). After step S9, the controller 26 finishes the preparatory operation. After finishing the preparatory operation, the controller 26 starts to execute the sorting operation, according to the control signal.

Upon deciding at step S6 that the first sheet sensor 231 is located at the upper-limit position (YES at step S6), the controller 26 decides that the output tray 21 is full (step S10), and transmits the information indicating the decision result to the controller 18 of the image forming apparatus 1, via the communication I/F 27 (step S9). After step S9, the controller 26 finishes the preparatory operation.

Now, a technique to detect whether an output tray included in the sorting device is full is generally known. However, the known technique is not designed to decide the loading level of the output tray, in small increments. If the loading level of the output tray can be decided in small increments, it is expected that the user-friendliness of the sorting device is further improved.

With the configuration according to the foregoing embodiment, the sheet detecting position of the first sheet sensor 231 is shifted in stages, and therefore the loading level of the output tray can be decided in small increments.

The sheet P delivered from the switching device 23 toward the output tray 21 falls owing to the self-weight, onto the output tray 21. The falling distance of the sheet P varies depending on the loading level of the output tray 21. Naturally, the lower the loading level of the output tray 21 is, the longer the falling distance of the sheet P becomes, and the less stable the posture of the sheet P becomes.

With the configuration according to the foregoing embodiment, however, the controller 26 causes the switching device 23 to stop moving, at the time point that the first sheet sensor 231 ceases to detect the presence of the sheet P. For example, when the loading level of the output tray 21 is “equal to or higher than 50%, but lower than 60%” as shown in FIG. 6C, the controller 26 causes the switching device 23 to stop moving, after lifting up the first sheet sensor 231 by six stages. Thus, the height at which the switching device 23 is located is adjusted according to the loading level of the output tray 21, so that the falling distance of the sheet P is shortened. As result, the sheet P can be prevented from assuming an unstable posture.

In addition, the known sorting devices generally include a sensor exclusively for adjusting the movement of the component corresponding to the switching device 23. According to the foregoing embodiment, unlike the above, the motor that accepts the positioning control is adopted as the drive motor 244. Such a configuration eliminates the need to employ the mentioned sensor, thereby preventing the complication of the apparatus.

FIG. 7A is a schematic front view showing a part of the structure of the switching device 23. As shown in FIG. 7A, the switching device 23 includes the delivery roller 238, a first guide member 233, and a second guide member 234. The delivery roller 238 delivers the sheet P to the output tray 21. The first guide member 233 and the second guide member 234 are located downstream of the delivery roller 238, in the delivery direction of the sheet P. The first guide member 233 and the second guide member 234 serve to guide the sheet P, from the upper and lower sides, respectively.

The first guide member 233 and the second guide member 234 are curved in the curl direction opposite to the curled shape of the sheet P. Therefore, the curl of the sheet P can be rectified. The first guide member 233 and the second guide member 234 are formed such that the gap defined therebetween, for the sheet P to pass through, gradually becomes narrower toward the output tray 21. In other words, an outlet 236 is narrower than an inlet 235.

FIG. 7B is a schematic cross-sectional view showing a part of the structure of the first guide member 233 and the second guide member 234. On the guiding surface of the first guide member 233 and the second guide member 234, along which the sheet P is guided, a plurality of ribs 237, extending in the direction orthogonal to the sheet delivery direction, are provided at predetermined intervals. Since the gap between the first guide member 233 and the second guide member 234 gradually becomes narrower in the sheet delivery direction as described above, and the ribs are formed on the guiding surface, the space that allows the sheet P to move in the up-down direction is reduced, and therefore the sheet P can be prevented from being curled.

Here, in the case where the posture of the sheet P delivered to the output tray 21 is unstable, the loading level of the output tray 21 may fail to be accurately decided, owing to misdetection by the first sheet sensor 231.

Therefore, the sorting device 2 according to another embodiment of the disclosure further includes, as shown in FIG. 8 , a second sheet sensor 800 that detects the leading edge or the trailing edge of the sheet P newly delivered to the output tray 21. The controller 26 decides the loading level of the output tray 21, when a predetermined time has elapsed after the second sheet sensor 800 detected the leading edge or trailing edge of the sheet P newly delivered to the output tray 21. The predetermined time corresponds to the time for the sheet P to fall onto the output tray 21 owing to the self-weight, and assumes a stabilized posture. For example, the controller 26 acquires the detection signal from the first sheet sensor 231, when the predetermined time has elapsed. Such an arrangement further improves the decision accuracy of the loading level of the output tray 21. Here, the first sheet sensor 231 may be configured to also act as the second sheet sensor 800.

The disclosure may be modified in various manners, without limitation to the foregoing embodiment. The configurations and processings described in the foregoing embodiment and variations with reference to FIG. 1 to FIG. 8 are merely exemplary, and in no way intended to limit the disclosure to those configurations and processings.

While the present disclosure has been described in detail with reference to the embodiments thereof, it would be apparent to those skilled in the art the various changes and modifications may be made therein within the scope defined by the appended claims. 

What is claimed is:
 1. A sorting device that sorts sheets, the sorting device comprising: a plurality of output trays aligned in a predetermined direction, and configured to receive the sheets; a first sheet sensor that detects a sheet placed on the output tray; a displacement mechanism configured to move the first sheet sensor in the predetermined direction along the plurality of output trays, in a predetermined increment of displacement amount; and a controller including a processor, and configured to, when the processor executes a control program: change a sheet detecting position of the first sheet sensor in stages, by controlling an operation of the displacement mechanism so as to move the first sheet sensor in the predetermined increment of the displacement amount; and decide a loading level of the output tray, according to whether the first sheet sensor has detected the sheet.
 2. The sorting device according to claim 1, wherein the controller causes the displacement mechanism to stop movement of the first sheet sensor, when the first sheet sensor ceases to detect the sheet.
 3. The sorting device according to claim 2, further comprising a switching device that changes a transport direction of the sheet and guides the sheet to one of the plurality of output trays, wherein the first sheet sensor is provided in the switching device, the displacement mechanism is configured to move the switching device in the predetermined direction along the plurality of output trays, in the predetermined increment of displacement amount, and the controller causes the switching device to move, by controlling an action of the displacement mechanism, and causes the displacement mechanism to stop the movement of the switching device, when the first sheet sensor ceases to detect the sheet.
 4. The sorting device according to claim 1, wherein the switching device includes: a delivery roller that delivers the sheet to the output tray; and a first guide member and a second guide member provided downstream of the delivery roller in a sheet delivery direction, and configured to guide the sheet from an upper and a lower side, respectively, the first guide member and the second guide member are curved in a curl direction opposite to a curled shape of the sheet, and the first guide member and the second guide member are formed such that a gap defined therebetween, for the sheet to pass through, gradually becomes narrower in the sheet delivery direction.
 5. The sorting device according to claim 4, wherein a plurality of ribs, extending in a direction orthogonal to the sheet delivery direction, are formed on a guiding surface of each of the first guide member and the second guide member at predetermined intervals.
 6. The sorting device according to claim 1, further comprising a second sheet sensor that detects a leading edge or a trailing edge of the sheet newly delivered to the output tray, wherein the controller decides the loading level of the output tray, when a predetermined time, corresponding to a time for the sheet to fall onto the output tray owing to self-weight, has elapsed after the leading edge or the trailing edge of the sheet is detected by the second sheet sensor.
 7. The sorting device according to claim 2, wherein the plurality of output trays are aligned in a vertical direction, and the controller causes, by controlling an action of the displacement mechanism, the first sheet sensor to move upward, from a predetermined lower-limit position of the output tray. 